The invention relates to a process for the manufacture of substituted 3-sulfopropyl ammonium betaines.
Examples of this class of compounds are used as components of laundry and cleaning agents since they exhibit excellent cleaning power at low temperatures in a suitable formulation; they are further employed as thermostable antistatic agents for molded masses of artificial material as well as coating material for textiles and woven fabrics. Sulfobetaines are also used as emulsifiers and as flotation agents. Good biological degrading ability is of special interest in the mentioned fields of application.
It has also been known to obtain sulfobetaines derived from 2-hydroxy-propane sulfonic acid through alkylation of tert. amines with 3-chloro-2-hydroxy-propane-1-sulfonic acid (DE-OS No. 24 31 031). The synthesis requires application of temperatures from 100.degree. to 135.degree. C., pressure, as well as the use of a considerable excess quantity of alkylation agent, wherein, however, yields of 75% average are obtained. The products are adulterated and difficult to crystallize. A further disadvantage of this synthesis process may be observed in the multi-stage synthesis of the required alkylation agent: glycerine-1.3-dichlorhydrin is obtained starting from allyl chloride, through the addition of HOCl, the epichlorhydrin from that and, ultimately, 3-chloro-2-hydroxy-propane-1-sulfonic acid through conversion with sodium sulfite. Therefore, this synthesis of sulfobetaine is not economical. Further, it has been known to produce sulfobetaines from tert. amines through alkylation with propane sultone (DE-AS No. 24 09 412). The propane sultone is obtained starting with allyl chloride by way of allylalcohol and 3-hydroxypropane-1-sulfonic acid as intermediates. Propane sultone is considered one of the most serious carcinogenic substances and its use, especially in synthesizing processes on a technical sale, requires special preventive measures (H. Druckrey, R. Preussman and collab., Z. Krebsforschung 75 (1970); 69; Registry of Toxic Effects of Chemical Substances, National Institute for Occupational Safety and Health, Maryland, U.S. (1975), 826).
In addition, it has been proposed (W. M. Linfield and colleag., J. Amer. Oil Chem. Soc. 53 (1976), 60; 55 (1978), 87) to add hydrogen sulfite to trialkylallylammonium salts for the synthesis of sulfobetaines of formula II. The conversion requires the simultaneous action of organic peroxide and hydrogen sulfite on allylammonium salts, wherein temperatures from 90.degree. to 100.degree. C. and reaction times of seven hours are required: ##STR1##
Care should be taken to exclude the oxygen from the air when rinsing the reaction mixture with nitrogen. Other disadvantages of this sulfobetaine synthesis are the use of organic solvents, the long reaction times, as well as the mode of operation under pressure in autoclaves. The products obtained are not chemically uniform but comprise isomeric sulfobetaine III, besides the principal product II.
Moreover, additions of hydrogen sulfite radicals to unsubstituted olefins in the presence of peroxides have already been known from Houben-Weyl, vol. 9, page 380, This leads to yields of about 60%. In Houben-Weyl loc. cit. p. 382, chapter B, the statement is made in the example of the addition of hydrogen sulfite radicals to allyl alcohol that the use of catalytically acting heavy metallic ions in the presence of oxygen as opposed to the use of peroxides as catalysts results in an increase in yield by 50% besides other advantages. DE-OS No. 23 31 515 covers a corresponding process for the addition of hydrogen sulfite radicals to unsubstituted olefins, in which transition metals of the 1st, 7th and 8th secondary groups of the Periodic Table of the Elements are employed as catalysts in lieu of peroxides.
The olefins employed in this process, however, are not comparable with the trialkylammonium salts (positively substituted in the allyl position) of this invention since they are unsubstituted, i.e. contain double bonds (DE-OS No. 23 31 515) or are negatively substituted (Houben-Weyl, vol. 9, p. 382) and thus considerably differ from the allylammonium salts of the present invention concerning their electron configuration and reactivity.